The MPL
by Idabit
Summary: One day as Sans, nicknamed Blue, is headed to train with Captain Alphys, he hears a voice eerily similar to his, and is suddenly part of a group which he didn't sign up for. What will his brother think, if he finds out at all? Rated T for eventual cursing, and possible bloody stuff. Contains other AUs, and a few I made... (Yes, I made the cover image.)
1. CH 1 - Blue

Sans stood in his bedroom, absently gazing at his freshly made bed. He had already cleaned his clothes, reorganized his closet, tightened the screws on his racecar bed, and straightened the frames on the walls, but he still felt there was something he had to do. He thought for a moment, then nodded. That was it. Make tacos.

The skeleton sporting a shockingly blue scarf stepped down the stairwell, heading to the kitchen. It was only then, when he wasn't looking where he was going, he tripped. Turning to see what he had fallen over, he realized it was his lazy brother, Papyrus. He was sitting up, preparing to yell, when the pile of bones groaned, and looked up at him.

"Mornin' bro…" He mumbled, lazily lifting up a hand to wave, then gave up, setting it back down. "What're you doin' on the floor?"

"I tripped over you!" He shouted accusingly, then added, "I was about to ask you the same thing."

"I'm just chillin', thought I'd keep the floor company. It looked _board_." Sans groaned at the pun, facepalming both inwardly and outwardly. "Besides, I heard ya working up in your room, didn't wanna interrupt by asking for tacos."

Ah. So he was hungry, but too lazy to get off his butt to go ask for food, let alone make some for himself. Sighing, Sans stood, entering the kitchen to make his signature dish. Captain Alphys had been teaching him how, and he knew he was better than her, but didn't want to admit it. He didn't want a battle axe in his skull.

Soon, they were seated on the couch, watching television, and eating tacos. Sans had tried to sit at the table, but Papyrus had said he working himself 'to the bone' lately, and he needed a break. In truth, he did. He had been training harder than ever to join the Royal Guard, and he was exhausted. Content from eating a good lunch, as well as sitting comfortably, he began drifting off into dream land. He hated when he fell asleep on the couch.

• • •

If he was being truthful, Papyrus hadn't actually just flopped on the floor out of boredom earlier. He had been up all night working in his lab, and he was tired. He had lied about going to bed at ten the night before, but instead headed downstairs to attempt yet again at fixing his machine. Only when he realized that it was eight AM, he decided it was time to get some sleep in any way, shape, or form. In his case, a six hour nap on the floorboards. Too tired to even drag himself to the couch, he had collapsed then and there on the floor. He didn't mind how uncomfortable it was.

He was still way too tired, thanks too the fact that he was always tired anyways. He began to nod off as well, drooping against the arm of the couch.

• • •

When Sans awoke, he realized a loud rumbling noise was coming from his right. Rubbing the sleep out of his eyes, he turned, and immediately identified the sound. It was his brother's snoring. Sighing yet again, he stretched, standing in front of the long sofa. He checked the time. Five PM. It was nearly time to train with the captain, which would be at six thirty. He tiptoed up the stairs, careful not to wake Papyrus. He knew what time he had really gone to bed. He pulled the freshly cleaned battle body out of his closet, and began to change into it.

Why did his brother always stay up so late in the basement? He'd eventually ask, but now wasn't the time. He began to busy himself, seeing as he still had an hour and twenty minutes. He cooked dinner. He would be dining with Alphys and Doctor Undyne, but he didn't want Papyrus to eat that greasy food at Muffet's.

Next, he decided to clean his brothers room. It had always been bugging him. He made the bed, and began picking up clothes and garbage randomly strewn about. He decided to leave the trashnado alone, taking care of the rest of the mess. Once finished, he aimlessly wandered around the house, searching for something to do, until he realized the other skeleton still slept on the couch.

Sighing the third time that day, Sans picked up Papyrus with blue magic, and brought him to his room. He tucked him into bed, and decided to leave him a note. ' _I'm going out to train with Captain Alphys_ ,' it read, ' _there's some lasanga in the fridge for you (I decided to try something new), so help yourself when you get hungry for dinner! See you later, Sans_ '

He folded it, standing it up beside the mattress where it would be obvious. He shut the door behind himself, and made his way down the stairs yet again. He grabbed his house key, and locked the door once he was outside. He buried his face in his small scarf, and made his way out of Snowdin, then through Waterfall. He created a narrow bone out of thin air, and tossed it as he walked.

"Hey," a voice eerily similar to his spoke, except just barely deeper, and he whipped around, dropping the bone with a clatter. It dematerialized as he began to shake a little. Deciding after a moment that it may have been an echo flower that had picked up his own voice, he shook it off, continuing on his way.

"If Captain Alphys burns her house down again, I'm going to be disappointed in her…" he mumbled. "And _I'm_ the student!"

"Hey Blue," he heard the voice again, and jolted when he felt a hand grab his shoulder. "You're bein' recruited."


	2. CH 2 - sans

CH. 2 - AU

He shook as he slowly turned around, half expecting to see Alphys. She occasionally played mean pranks on him like that. What he did see shocked him even more. It was like he was staring into a mirror. A mirror wearing different clothes, that is. He stared at a skeleton as short as he, the same eye sockets, same nose, same mouth, same everything! The only difference was he wore a blue jacket with a grey hood, black shorts, and fuzzy pink slippers.

"What the heck?!" He was strictly against profanity.

"Heya," his mirror said, "I'm Sans, Sans the skeleton. Also, you from another AU, mister swap me."

"What in Toriel's name is an AU?!" He demanded

"Alternate Universe," he answered simply, then added, "in my case, I'm from the original. I'm the only one who goes by our real name."

"Y-y-you say that like there're more…" He began to stutter. He didn't stutter often. The other version of him nodded.

"Sure are. Tons actually, but not all of them are nice… That's why we're recruiting all of the not actually evil versions of us. That means you're joining us as well." The swap version was silent for a moment. The faint rushing of waterfalls in the distance was the only sound.

"What exactly am I being recruited into…?" He finally spoke. Sans, the original, grinned a little.

"MPL," his voice dropped as he answered in short, "the Multiverse Protection League." Another pause.

"Do I have a choice…?" He began speaking quietly as well. Now the original's face fell.

"Not really…" he muttered, his whisper still loud enough to echo through the cave walls. "Wish ya did, I really do. But guys like Nightmare n' Error don't exactly give people chances. And I'm also sorry that it won't be that safe…" Yet another silence from the swapped version.

"Can I tell Papyrus?" Now it was the other's turn to not say anything.

"No…" He mumbled. "We already had to stabilize the Multiverse to be able to handle us all being in the same place, as well as travel across AUs. If we have a whole other monster, we may not be able to keep it stabilized. Horrible glitches could occur. The whole thing could very well collapse in on itself, AKA, the end of the world. All worlds."

"Do I have to go soon?"

"Yep."

"How soon?"

"Now." The original took his hand, and lit up his left eye. He snapped the fingers of his free hand, and the scenery around them blurred as it changed into something completely new.

Right beside where the swapped Sans had stood was a small blue echo flower. It had listened to everything they said, and would now repeat it to anyone who cared to listen to it.

• • •

It was now eleven, and Sans still hadn't returned. His training sessions usually lasted about two hours, even with the added dinner and company it should have been at least four hours. He should have been there thirty minutes ago. Papyrus had received a message seemingly right after his brother had left, which told him he would be back by ten thirty. He was never late.

"Where the hell is he?!" The tall skeleton demanded from the empty house, but of course received no response. It was a house, after all. He was fed up with waiting. He teleported to Alphys' lizard shaped house, and pounded on the door nonstop until the tired reptile opened it.

"Whaddyawant…?" She slurred, rubbing her good eye.

"Is Sans still here?!" Papyrus demanded, putting his hands on her shoulders, shaking her awake. She didn't need that to wake up, though. Only the question.

"I-I thought he was sick at home or something!" She seemed worried now. They were best friends. He stopped shaking her. He stood, paralyzed by the fear of what could have happened to his brother. What if someone had dusted him?!

"Shit… I'm going to track his magic," he said firmly. Without waiting for the captain to say something, he teleported back to his house, and began to track his magic. Each monster had it's own magic pattern. It wasn't exactly like a pattern, though. It was more like a smell, though you couldn't smell it, or sound, though you can't hear it. Just something one could sense.

He followed the magic, and was going through Waterfall when he stopped. He sensed a large burst of magic, similar to, but not his brother's. The burst steadied, as it seemed to follow Sans'. He tracked, until they both just stopped. There was another, larger burst of magic here. He felt as if his soul had shattered.

Had his brother been… killed…? No. He couldn't sense the feeling of magic dying. It wasn't an attack. It was a teleport. But Sans couldn't teleport! That only left two options; he had gone with someone willingly, or he had been kidnapped. The latter seemed more likely. Papyrus had warned him about strangers, and he would never go off track unless it was extremely important.

Papyrus felt something both warm and cold at the same time inside his soul. It wasn't joy. It was anger. Pure, seething rage.

He didn't acknowledge the little blue flower at his feet. His mind was too clouded by anger. He only had one clear thought running through his head. Whoever had taken his brother, well…

They were going to get one hell of a bad time.

• • •

After Alphys had called Undyne to check her surveillance cameras for Sans, she received a call from his brother.

"Have you found him?!" She was fearful for his life. He was the kind of person that was too sweet and innocent to hurt. You would have to be pretty cruel to do so.

"No," came the reply from the other line, "but I'm afraid someone else already did…" Her jaw dropped. When she didn't reply, he continued. "I think he was teleported somewhere. I sensed his magic and somebody else's, then both just vanished. It was like my magic."

"I called Undyne to search the cameras," she informed the skeleton. "She told me she would scan for his magic if she can't find him."

"Thank you…" he whispered.

• • •

Papyrus had finally noticed the echo flower on the ground. Crouching down, he began to listen to the message. At least what he could hear.

"What the heck?!" He heard his brother.

"Heya," a slightly deeper, yet similar voice spoke, "I'm… AU, mister swap…" Most of it was inaudible.

"What in Toriel's name is an AU?!" That he could hear. Thank goodness for his loud voice.

He didn't hear the answer. "In my case, I'm from… the only… real name…"

"Y-y-you say…" He heard a stutter in his voice. That was uncommon.

"Sure are. Tons actually, but not all of them are nice… why… recruiting all of… not… evil… joining us…" There was a moment of silence.

"What exactly… into…" His brother finally spoke. The other said something he couldn't quite make out. "Do I have a choice…?"

"Not really…" he heard. "But… don't exactly give people chances… won't be that safe…" Silence again.

"Can I tell Papyrus?" The other didn't speak this time.

"No…" He finally heard. "We already had to stabilize… If… whole other… we may not be able… glitches… collapse in on itself… end of the world…"

"Do… soon?"

"Yep."

"How…"

The last words couldn't be heard. Papyrus was frustrated that he couldn't hear it. So he was in danger as well. Soon, he got another call. He quickly whipped out his phone, but his face fell when he saw it was Alphys, not Sans.

"Undyne can't find him on the cameras…" Her voice wasn't nearly as upset as he. "The one in Waterfall was broken by something…"

"And the magic scanner?" Obviously not.

"No sign of him either…" A shout could be heard from his end of the line.

"Can you ask Undyne something?" Came an eventual question.

"Yeah, what is it?"

"Ask her to research what an AU is…"

"A-alright…"

He hung up without another word. If any harm came to his little brother, then the Underground may as well be renamed 'Hell on Earth'.

 **So, that was chapter two. I know, they're currently really short. Don't worry though! I'm going to gradually make them longer. I just hope this really kicks off! I did this chapter today as well to make up for how short they were. I won't exactly have a strict updating schedule, but I'll try my best! Now, I've already stayed up too late doing this for you. I'll get chapter three out ASAP!**


	3. CH 3 - Ink n' Nicknames

CH. 3 - Ink n' Nicknames

When the two versions of Sans arrived at their destination, the swapped version of the two stared in awe at the sky. It was nighttime, and millions of twinkling dots resided in the sky. Stars.

He had never actually seen real stars for himself before. It was… breathtaking. "Where are we…?" He had trouble tearing his gaze away.

"Ink's universe," he answered, "or at least what's left of it… his entire world was destroyed by Error. He had tried to save it, but couldn't bring back the people. The many versions of us are the only inhabitants."

"That's… sad…" He couldn't imagine what it would be like. Losing all his friends, his brother, even strangers he would never meet, the whole idea just seemed depressing to think about.

"Hey Sans!" He turned, about to say something, when he realized the newcomer was addressing the original. "I see you recruited the swap Sans." Sans nodded. "Well, I'm gonna give him a nickname before things get too confusing." He looked him over.

"I've already dubbed him Blue," Sans informed him. He didn't question it, just accepted the name as his own. The other nodded, then turned back to Sa- no, Blue.

"Heya Blue," he greeted the cyan themed skeleton, "I'm Ink. Welcome to my universe!" So this was Ink. The death of his world must have been a long, _long_ time ago, since there seemed to be no traces of sadness left on his face.

"Heya…?" It was more of a question than a greeting. In the distance, he saw another version of himself, except this one seemed a bit worse for wear. He had a large crack running through his skull, bags beneath his eyes (if that were possible for a skeleton), and sharp teeth, one of which was golden. He wore a heavy black jacket, which had lots of fluff on the hood.

"I got the reports on Nightmare's current whereabouts," he spoke with a deep, rumbling, baritone voice, then added in a growl, "next time don't go disappearin' when I'm gettin' you something…."

"Thanks," Ink took the pages, and turned to the newest recruit. "Hey Blue, this is Red."

"How many of us are nicknamed after colors?" He had his priorities. "Oh, and… hi."

"Sup," he practically snarled. He didn't seem angry at anyone though. Frankly, he only looked slightly annoyed. "To answer your question, a bunch, just not all of us. These guys just aren't very creative."

"Aren't your brothers worried?" So many questions flooded into his head, nearly all spilling out with the one. Suddenly, he had a sinking feeling. _Papyrus must be worried sick_.

"I've been telling Paps that I'm working as a sentry for Asgore," Sans explained, "he believes it, though I feel bad for lying to him. He's a bit gullible…"

"My bro just doesn't give a shit about me," Red seemed to be telling the truth. Poor guy.

"Anyway, come along Blue," Ink ordered.

"For what?"

"Orientation."

• • •

Papyrus wasn't just mad. He was absolutely pissed. If somebody had the audacity to take his brother, and expect to be fine, they had a whole other thing coming. He still stood at the little echo flower, listening to the message over and over. It was no use, though. He just couldn't hear the parts. In a fit of rage, he brought his fist down on a nearby stone, splitting it in two. He stared blankly at it.

He just didn't understand. Out of all the monsters in the underground, why his brother, why Sans? And… why was the magic of the kidnapper so similar? He heard a familiar medley come from his pocket, and he pulled out his phone. It was Doctor Undyne.

"What did you find out?!" He immediately asked after picking up.

"A-a-ab-about th-the AUs?" She managed to stutter out.

"Yes, _dammit_!" He shouted, then heard a squeak and a muffled crash as she dropped her cell.

"O-o-oh! I-I found so-s-some of the o-o-old royal s-scientist's writing, b-b-but I c-could only fi-find out they're similar to-to timelines… a-and those are on-only a theory themse-themselves! I'm s-s-so sorry… I-I'm trying, I-I really- I really am…" That didn't ease his emotional pain.

"Call me again when you find out more."

"O-o-okay-" _Click_. He hung up before she could speak. So many emotions ran through his head. Sadness. Fear. Emptiness. Anger. Confusion. Helplessness. Rage was the only clear, distinguishable emotion.

• • •

Ink lead Blue to the biggest tree he had ever seen. It must have been at least a mile high! It was possibly eighty feet around on the trunk. Impossibly big. He looked at the other skeleton. "How…?" He gestured to the colossal oak with giant branches splaying this was and that.

"Literally magic. This thing's ancient, and many monsters, me being one of them, enhanced the growth to make it bigger than the rest. Sadly, it eventually died, and we hollowed it out for headquarters." Blue stared in awe at it. "Of course, on the outside we built an exoskeleton to keep it from collapsing. We're working on the inside." Another Sans approached them, handing Ink a little pouch, which he pocketed with a nod of thanks.

This version sported camouflage pant with varying shades of grey, a brown leather jacket with a golden star inside a circle on each shoulder, and plain white shirt. He also wore black, fingerless gloves, and a strap with empty loops across his left shoulder, to the right side of his waist. On his face were very light scratches. Upon closer inspection, he noticed one of the smaller details on the jacket, a dark blue, metal brooch with an echo flower insignia. Sans, Ink, and Red all wore one of these brooches as well, he noted.

"Sup. I'm Camo." He extended a hand, which Blue hesitantly took, then shook. "Who're you?"

"Blue," he introduced himself. "Nice to meet you." After a moment of relatively awkward silence, Ink dragged him into the tree, then teleported them into one of the farther reaches of the trunk. A door labeled ' _Ink's Office_ ' stood to the right, while to the left were doors belonging to different Sans's, like ' _G_ ', or a much smaller one, ' _Meowzer_ '…? (Nicknames, am I right?) Ink lead him into his office, and took a seat. There were random splashes of color everywhere, and a large paintbrush mounted on one of the walls.

"Alright," he began, standing in the center of the room, "welcome to the MPL. We are the Multiverse Protection League, guardians of the millions of universes out there. We ensure the safety of every timeline, of every Papyrus, Toriel, Asgore, everyone. I know you may not be the strongest monster out there, but we'll train you."

"Mm." Blue nodded. Ink approached him, taking the pouch Camo had given him out of his pocket, then opening it. He stopped in front of the newest recruit, and pulled a small brooch out, similar to the one he and the others wore. He somehow pinned it to Blue's armour, near the left shoulder plate. He guessed it was magic allowing it to stick.

"If you're in trouble, all you need to do is hold it, and ask for help in your mind," Ink explained, "It's a bit like telepathy. You don't necessarily need it just for emergencies, but for communication in general." Another nod from Blue. Silence. "Well, that's all!" He clapped his hands together. "Sans'll take you home, so just wait a moment." He clasped his own brooch, and moments later, the original appeared out of thin air.

"Heya. You ready?" He held out his hand.

"Y-yeah…" Blue tentatively took it. This whole thing was a lot to take in. Sans lit his eye with cyan and yellow magic, and their surroundings blurred with a snap of his fingers. When the world came back into focus, Blue was back in his house, in the living room.

"Seeya 'round kid," Sans waved a hand, then teleported away. He wondered if he would learn how to do that.

• • •

 **Heyo! Idabit here, sorry for the late upload! I was working on this, I swear, but school just dumped a shit-ton of work on me, as well as playing tests in band I had to practice for! Again, I apologize for the short chapters, I've trying my best. I'm not sure when chapter four will be out, you'll just have to be patient. Sorry! Anyway, about Camo, he's actually from a currently nameless AU I'm working on. Have a good morning/day/evening/night, whatever time it is for you. Unless you're in the void. In that case... I dunno.**


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